Some modified drivers lack a valid driver signature and this prevents them from being installed on a 64-bit Windows OS. To bypass this restriction and be able to install those drivers you need to run Windows in Test Mode or boot Windows with “Disable driver signature enforcement” option. These methods are only needed for x64 versions of Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows Server 2008, Windows Server 2012 and Windows Server 2016.